Anyone knows the name of the illusion? It was on Copperfield's Tornado of fire. He asked the audence do the same. He used a hands trick.

It goes by many different names. It is an old trick. I call it Writs Rotation. You can find an inexplaination in Andrew Mayne's Body Morphin'

I found it kind of funny that they cut the camera away when he said "PUT YOUR THUMBS DOWN" as he separated his hands and did the "move"

It's amazing what you notice when you know what the secret is. This is a good point about controlling every aspect of a show. From choreography (not just dancing but also just how to stand and what to do with your hands, head while talking) to lighting and camera shots. A good showman trys to control as many aspects as possible to put on the best show. And that's even without any tricks.

Kyle I know how its done I just didn't know the name of this illusion

Bill thanks for the name